This invention relates primarily to improved permanent calender constructions and, more particularly, to improvements in the means for detachably securing the vertical data columns to the main calender body member and for calender stands.
In my previous application, I have confronted and solved the problem of varying month lengths. In other words, I have provided means for varying the number of visually exposed numerals appearing on several of the vertical data columns. Depending upon the particular month in question, it is necessary every month to rearrange and reposition the vertical date columns, as well as adjust the rotatable members to account for the fact that months have varying lengths.
Two contradictory goals must be resolved. First, it is necessary to keep the vertical date columns firmly secured to the main body member so that the columns do not fall out easily from their normal positions, no matter what the position is of the main body member. Second, it is important that the columns be easily removable so that they may be rearranged on the main body member with a minimum of effort, and without requiring the calender to be taken apart or to be taken off its normal viewing position or from its permanent attached position.
In the prior art references, those versions which are simple to rearrange have a design that allows the columns to fall off the main body members very easily. An example is U.S. Pat. No. 301,553 in which it can be seen that the portions D which rest uon the portion B are such that the columns may be easily removed and may be easily slid horizontally along the tracks to adjust the calender accordingly. However, as best seen in FIG. 1 of this reference, should the unit be tilted forward, there is nothing to prevent the element D from passing outwardly through the two members B within which it is esconced, and thus the vertical date columns will fall off the tracks B. Experience has shown this to happen quite often when changing the position of the columns, and this is quite annoying.
On the other hand, those prior art calenders which are structured to allow the columns to be securely maintained to the main body member, do so only at the cost of having to remove all of the columns in order to change any of them, or having to take the calendar apart to remove the columns, or removing the calendar from its normal position, such as the wall, requiring more effort than it is felt is necessary. An example of such prior art is U.S. Pat. No. 247,000. This reference discloses means to retain the vertical column blocks f in position. To change the blocks around, the whole unit must be disassembled by the removal of the slide h out of position in the side scripts a. The blocks are retained in position at the top by the slide g. The whole unit obviously must be disassembled to allow rearrangement of the calendar.